1. Field of the Invention
The present invention relates generally to fixing technologies, and more particularly, to a heat sink fixture for fixing a heat sink to a heat generating device.
2. Description of Related Art
Computing speed of the present computer system is increasingly faster, and the amount of operations becomes increasingly larger, so when the computer is under full load, surface temperature of a processing unit, e.g., a Central Processing Unit (CPU) or a microprocessor, that can generate a great deal of heat, often may be higher than 100° C. Thus, in order to solve such an overheating problem, one common approach is to provide a heat dissipating apparatus, such as a heat sink, a fan and the like, in the computer, so as to dissipate the heat that is produced by the heat generating device (CPU or microprocessor).
To assemble a heat sink in a computer, a heat sink fixture is usually used to closely press the heat sink against the heat generating device and fix it in place, so that the heat sink does not easily slip away or loosen and will be able to dissipate heat efficiently as required. The heat sink fixture is very critical to heat dissipation, since if there is not a good heat sink fixture even the perfect heat sink is useless. The ideal heat sink fixture allows the heat sink to make even and close contact with the heat generating device, thereby decreasing the thermal impedance between the interfaces and enhancing the heat-absorption capacity of the heat sink bottom. There are many related patents that disclose heat dissipating fixtures, for example, Taiwan Utility Publication No. 246,982 and No. 564,009.
The Taiwan Utility Publication No. 246,982 proposes a latching member structure between a CPU and a heat sink. The latching member structure is essentially a metallic bar. A leaning section is provided at the centre of the metallic bar, and both sides of the leaning section symmetrically extend and slant upward to form spring members. From the tail of each spring member, a fastener extends downwards and an ear portion extends upwards. The bottom part of the fastener forms a latching hole. During assembling, the latching member is disposed in a slot of the heat sink, in that the leaning section acts as a pivot and the fasteners at either side of the leaning section are moved downwards by pressing the spring members, so that the latching holes are latched to projections symmetrically provided on the corresponding sides of a CPU socket; while disassembling, the latching hole can be unlatched from the projections by pulling the two ear potions inwards, thereby making disassemble and assemble conveniently and preventing distortion due to overheating.
However, the above-discussed latching member structure between the CPU and the heat sink employs the leaning section at the middle of the latching member to directly press against the heat sink. During assembling, the leaning section experiences pressure due to deformation of the spring members. The force exerted onto the heat sink is only through the small area at the bottom of the leaning section, in other words, the pressure is not evenly applied to the heat sink such that the CPU and the heat sink cannot be closely combined together, thus degrading the heat dissipation.
Moreover, since the contact area between the latching member and the heat sink is small and the applied pressure is constrained, the fixing of the heat sink is unstable and easy to slide due to improper contact or vibration when maintaining, such that the contact area between the CPU and the heat sink may be decreased, resulting in poor heat dissipation of the CPU.
Taiwan Utility Publication No. 564,009 proposes a latching apparatus that closely joins a heat sink with a heat generating device. The latching apparatus for the heat sink is made by bending an elastic metal spring strip to essentially have a pressing section and two arms. The middle of the force-exertion section is horizontally formed with a ring-shaped enclosing section, which is used to loop around a circular structure of the heat sink so that the latching apparatus is correctly oriented on the heat sink. Both ends of the enclosing section extend horizontally to form extending sections for pressing against the heat sink. The two arms are respectively formed at the end of extending sections extending at substantially vertically bent, and a hook is formed at both ends of the arms for fastening to corresponding component.
However, when applying the above-discussed latching apparatus for heat sinks, as shown in FIG. 1 (PRIOR ART), the area at the end 101 of each extending section of the two arms 10 available for pressing is small, it may cause pain to the fingers of assembly operators who need to frequently pressing the ends 101 of the latching apparatus. In addition, the pressing direction for this type of latching apparatus is shown by arrow A of FIG. 1 (PRIOR ART), which requires a much larger force to be applied for assembling.
Furthermore, during the process of assembling the above-discussed conventional latching apparatus for heat sinks, force must be imposed on both sides of the heat sink, accordingly, the space required for operation is inevitably larger than the physical space of the heat sink, which causes unnecessary space waste. Furthermore, the force applied to the heat sink is not even, so it also exhibits the problem of an unstable fixing as described previously.
Accordingly, there exists a strong need in the art for a fixing technology for heat sink that is capable of decreasing difficulty in assembling operation, reducing the space required for assembling and exhibiting a shock damping effect.